Revert "Change ThreadEnforcer ANY to NONE for clarity."

This reverts commit 4f8c074d4a8bb146af5779fe7ca9841a6d01c8bd.

Conflicts:
	CHANGELOG.md
	library/pom.xml
	pom.xml
	sample/pom.xml
Revert "Add OttoBus base interface, and have Bus implement it."

This reverts commit 74b789a0b970689de70a8990e2ad1ce7eba8478e.

Conflicts:
	library/src/main/java/com/squareup/otto/OttoBus.java